Air Conditioning

I have a 1993 Saab 900 non turbo. The guy I bought the car from is a Saab officionado. The car has r-12 air conditioning system which doesn’t work.The guy tell me that i either have to find r-12 or convert the system to the r-132(or whatever it is).The conversion would cost 1500.00. Other mechanics I spoke with said that my system could be retrofitted with the new refrigerant for about 150.00. My original guy said that the two sysytems are really imcompatible,in that the molecules are too different and that it may work for a little while and then foul up the system and mess up the seals etc.Who is correct? Is my solution to roll down the windows?

I suggest you call a shop that specializes in automotive HVAC systems and ask them for an estimate.

My guess is $1,500 is likely to be closer to the truth than $150.

All you’ll get for $150 is a fill with R-134A, which won’t work for long and will cause bigger problems.

The two refrigerants use different oils. The R-12 refrigerant uses mineral oil in the system. The R-134a refrigerant uses a PAG or ester oil in the system. To do a conversion correctly the mineral oil needs to be flushed out and either PAG or ester oil introduced.

Also, the desiccant material used in the drier for the R-12 refrigerant is not compatible with R-134a. So that needs to be swapped out for a new drier.

Listen to the guy that says it needs to be converted in order for it to work properly. He’s up on how refrigeration systems work.


To change over to R-134 the present lubrication oil has to be removed and the oil compatible with the R-134 added. This means a thorough flush of the system to get all the old oil out; draining the compressor; refilling the compressor; changing the receiver/dryer; evacuating the system; and recharging.

It is likely that a lot of O-rings and some gaskets will have to be replaced because they will deteriorate with the new refrigerant and oil. The expansion valve might have to be changed to help the cooling efficiecy. Also, you will have to find and repair whatever caused the R-12 to leak out and any damage that may have caused.

You don’t mention the geographic area you live in. If the climate is mild (coastal) and does not have humidity problems (Florida or South-east), you might get by without A/C. But in Las Vega, Bakersfield, Death Valley, etc. driving without A/C is uncomfortable to say the least – driving 4-70 at night is the only way to fly.

On a garden variety Chevy a proper, working, change over costs about $800, as I was quoted by a reputable A/C shop. On a Saab, everything costs a whole lot more, so $1500 is not out of line. There are still places where you can get R-12 at a very high price, since the manufacture of new R-12 ceased long ago. In the South, some unscrupulous places sell PROPANE to top up your system!!! I would stay away from those!

I agree with other posters that a 1993 Saab is not worth putting a whole lot of money in, since it already is an orphan. If you live in a moderate part of the country, roll down the window, or sell the car.

If the system is empty the first thing to do is repair the leaks; usually the Schrader valves at the service ports or the compressor shaft seal.

For what it’s worth, I “converted” my old SAAB (85 model running R12) to R134 by doing nothing more than adding a can of Ester Oil after fixing a service port leak and charging it up. It provided ice cold air on 100 degree days for 3 years while my oldest son took it off to college. After his schooling was over, I sold the car and it was still working fine at that point.

There was never a problem with it after doing this. By the book? No, but it worked. And it wasn’t the first one either.

I vote for finding out what is wrong before deciding. Nothing wrong with fixing a leak and re-charging with R-12. How much longer do you think your SAAB has left in it?

Look into this. I’ve never used it, but a quick google search led me to the page. Do some research first though.

Found it cheaper on ebay.

I know my recommendation was not a proper, by the book one. The reason I made it is because we’re talking about a 17 year old SAAB for which a high conversion price was quoted and the OP does not give the impression they want to spend 1500 bucks on this conversion; whatever that conversion may be. Not that I blame them.

That 1500 is way high unless there is something like compressor/condenser replacement involved.